Background: Adjuvant therapy for women with T1-T2 breast carcinoma and 1-3 positive lymph nodes is controversial due to discrepancies in reported baseline locoregional recurrence (LRR) risks. This inconsistency has been attributed to variations in lymph node staging techniques, which have yielded different numbers of dissected lymph nodes. The current study evaluated the prognostic impact of the percentage of positive/dissected lymph nodes on recurrence and survival in women with one to three positive lymph nodes.
Methods: The study cohort was comprised of 542 women with pathologic T1-T2 breast carcinoma who had 1-3 positive lymph nodes and who had undergone mastectomy and received adjuvant systemic therapy without radiotherapy. Ten-year Kaplan-Meier (KM) LRR, distant recurrence (DR), and overall survival (OS) rates stratified by the number of positive lymph nodes, the number of dissected lymph nodes, and the percentage of positive lymph nodes were examined using different cut-off levels. Multivariate analysis was performed to evaluate the prognostic significance of the percentage of positive lymph nodes in disease recurrence and survival.
Results: The median follow-up was 7.5 years. LRR, DR, and OS rates correlated significantly with the number of positive lymph nodes and the percentage of positive lymph nodes, but not with the number of dissected lymph nodes. The cut-off level at which the most significant difference in LRR was observed was 25% positive lymph nodes (the 10-year KM LRR rates were 13.9% and 36.7% in women with < or = 25% and > 25% positive lymph nodes, respectively; P < 0.0001). Higher DR rates and lower OS rates were observed among patients who had > 25% positive lymph nodes compared with patients who had < or = 25% positive lymph nodes (DR: 53.0% vs. 30.3%, respectively; P < 0.0001; OS: 43.4% vs. 62.6%, respectively; P < 0.0001). In the multivariate analysis, the percentage of positive lymph nodes and the histologic grade were significant, independent factors associated with LRR, DR, and OS.
Conclusions: The presence of > 25% positive lymph nodes was an adverse prognostic factor in patients with 1-3 positive nodes and may be used to identify patients at high risks of postmastectomy locoregional and distant recurrence who may benefit with adjuvant radiotherapy and more aggressive systemic therapy regimens.